The application claims priority under 35 U.S.C. xc2xa7xc2xa7119 and/or Patent Application Serial No. PR8512 filed in Australia on Oct. 26, 2001, the entire content of which is hereby incorporated by reference.
The present invention relates to a surface working device, such as for planing and grading roads, and to an attachable protector for the same.
Various road maintenance systems exist for working road surfaces. Such working may for example take the form of grading and planing a road, e.g., in order to provide a dirt road or the like with a smooth driving surface. It could also take the form of for example ice and snow scraping for keeping roads open in winter conditions, as well as asphalt planing and gravel maintenance.
As shown in FIG. 1, such systems typically include a planing blade 1 which breaks up and smooths the surface of a road. The blade 1 is mounted beneath a vehicle between the vehicle""s front and rear wheels F and R.
The planing blade 1 is generally angled to the direction of movement D of the vehicle, this angle (denoted xcex1 in FIG. 1) being changed dependent on, e.g., the hardness of the surface being worked.
One such known system is the Sandvik System 2000(trademark) provided by Sandvik AB of Sandviken, Sweden.
As shown in FIG. 2, this system utilizes a cutter board 2 that is attached to the planing blade 1 and has a plurality of rotating picks 3 mounted within it. The picks 3 break up the road surface as the grading vehicle advances.
Details of this system can be found in U.S. Pat. No. 4,784,517, the contents of which are incorporated herein by reference.
As the planing blade 1 is angled with respect to the vehicle""s direction of motion D, the leading edge 4 of the cutter board 2 (corresponding to the leading edge 5 of the planing blade 1) is subject to wear.
In order to counter this, an end protector 6, shown in FIG. 11, has been devised for the cutter board 2.
This end protector 6 is mounted on the cutter board 2 by bolts 7 (only one shown) which extend through bolt holes 8 of the protector 6 and similar bolt holes 9 in the cutter board 2 and in the blade 1.
The end protector 6 protects the leading edge 4 of the cutter board 2 against wear, and can extend the life of the cutter board 2.
The inventors of the present invention have found, however, that problems can occur when the blade 1 is used to grade or plane hard road surfaces, such as are often found on dirt roads and country tracks.
These problems can include a riding up of the protector 6 over the cutter board 2, so as to expose the leading edge 4 of the cutter board 2 to wear. Furthermore, the bolts 7 holding the protector 6 in place can sometimes loosen and shear off under the loading actions experienced during use.
The present invention aims to provide an alternative end protector that is designed to address such problems.
Viewed from one aspect, the present invention provides an end protector for a working element of a surface working device, the working element having a body portion with a plurality of holes therein for receiving pick elements, wherein the end protector is configured for attachment to the working element by the use of one or more of the pick holes.
From this aspect, therefore, the present invention can be seen to reside in the removal of one or more of the end picks from the working element, e.g., cutter board, so as to allow the end protector to be mounted to the working element through the unused pick hole or holes.
This may be achieved, for example, by having a fastening member, such as a bolt, extend into and/or through the or each empty pick hole and engage the end protector.
The use of one or more of the pick holes to mount the end protector in place provides a secure attachment that resists riding up of the end protector. Furthermore, the orientation of the bolt or other fastener within the pick hole helps to reduce the likelihood of bolt shear or the like.
An end protector attached in accordance with the present invention may provide good protection for the working element when for example it is used in the working of hard surfaces, such as compacted dirt tracks and the like, and may also be used, e.g., in mining board systems for, e.g., open cut mines, quarries and hard rock mines. It may also however be used with working elements in general across the range of working applications, such as ice and snow clearing and the like.
In many situations, the use of one pick hole to mount the end protector may be all that is required. For extra stability, however, one or more further pick holes could be used to mount the end protector, so that for example the two pick holes that are closest to the leading edge of the working element could be used.
The attachment of the end protector to the working element may take any suitable form, as may the shape and construction of the end protector.
In one preferred embodiment, the end protector is configured to slide onto the end of the cutter board, and includes at least one hole or slot that extends over a top and/or bottom opening of one of the end pick holes. A fastening element may then extend through the hole/slot and into the pick hole to hold the end protector in place.
For example, a bolt or other fastener may extend through a hole or slot in an upper face of the end protector, downwardly through the pick hole and into a recess in a lower portion of the end protector. In order to secure the fastener, the recess may for example be tapped or a suitable thread could be provided in the hole or slot in the end protector upper face.
Alternatively, the bolt or fastener could extend in the opposite direction, and as a further alternative, the recess could be replaced by a hole allowing the fastener to extend completely through the end protector and to be fastened by further means, such as a nut or the like.
As well as bolts, other fastening means could be used, for example screw, clip and/or bayonet type constructions could be used, and the bolt may be replaced by some other shaft member or stud element. Other fastening systems could include similar systems to those used to hold the picks in place in the holes, e.g., a split spring sleeve mounted on a bolt or shaft/stud element of the end protector which resiliently engages the insides of the pick holes.
In one preferred embodiment, the fastening element has a shank portion of narrower dimensions, e.g., diameter, than a head portion, e.g. so that the fastening element is of a stepped configuration. The stepped portion may provide a sharp transition or a more gradual curved transition.
In this embodiment, the transition, e.g., stepped, section between the head portion and the shank portion, e.g., a bottom surface of the head portion, may bear against the body portion of the working element so as to provide a force between the end protector and the working element in order to hold or assist in holding the end protector in place. This fastening element may screw into the end protector, and may include a threaded portion at the head portion and/or at the end of the shank portion for engagement with a threaded hole or recess in the protector. When the fastening is provided at the head portion, the shank portion need not be sized to extend completely through a pick hole, and may instead merely extend part way into the pick hole.
Although preferably of one piece construction and slidable onto the end of the working element, the end protector may be of, e.g., two-part construction, in which case the parts could be connected together on mounting the protector to the working element. They may for example be clamped or bolted together or otherwise fastened. In such situations, the actual fastening element of the end protector need not necessarily extend through the vacated pick hole or holes, rather a stud or the like could extend into or through the pick hole to hold the end protector in place, whilst fastening, e.g., the clamping together of the two portions of the end protector, could occur externally of the pick hole.
The end protector may be provided with one or more protective surfaces for protecting the leading edge of the working element on which it is to be mounted. These surfaces may take different forms depending on the use to which the working element is to be put. They may for example vary in size, orientation, number and material. This may depend for example on the type of roads and conditions in which they are designed to be used.
The protective surfaces may be made of a suitably hard material, e.g., a cemented carbide material, such as tungsten carbide, and may form an integral part of or be mounted onto the end protector. The amount of wear-resistant material used, its size and volume may vary depending on the applications and conditions in which it is to be used.
The end protector may include more than one protective surface, so that for example one surface provides more protection when the working blade is oriented in one direction, e.g., angled more towards the direction of travel of the grading vehicle, whilst another surface provides more protection when the working blade is oriented in another direction, e.g., angled more transversely with regard to the direction of movement of the grading vehicle. For example, one surface may provide (the main) protection between about 20xc2x0 and about 45xc2x0, whilst another may provide (the main) protection between about 45xc2x0 and about 90xc2x0.
In one preferred embodiment, the protecting surface or surfaces of the end protector may include one or more tool elements, e.g., of cemented carbide material. Such tool elements may be configured so as to provide a cutting, rolling and/or other working action to a surface during grading.
The end protector may also be provided with one or more tool portions to replace the pick element or elements that are removed from their holes in order to accommodate the end protector. The tool portions may be configured so as to provide a similar cut as the other picks in the working element. In one embodiment, a tool portion is configured so that in use the front tip of the tool portion is set just above the pick points of the picks.
These tool portions may also provide protection to the leading edge of the working element, e.g., when the working element is in a more transverse orientation with respect to vehicle advance.
The tool portions may take any suitable form, and may have a head that is for example similar to that of the picks. They may also be mounted within the end protector for rotation.
The working element will generally be mounted on the blade or the like so that in use it is angled to the vertical, e.g., it is inclined at an angle of about 20xc2x0 to the vertical. This can expose the back edge of the working element to wear, and the end protector is preferably configured so as to protect this back edge. In one embodiment, a hardened surface of the end protector, e.g., a tool portion, is configured so that, in use, it extends below the position of the back edge of the working element.
Besides being angled to the direction of travel and to the vertical, the working element (and, e.g., the blade to which it is attached) may be positioned in use so that one end is lower than the other, e.g., it is rotated from a horizontal position about an axis extending in the direction of travel of the vehicle or the like to which it is attached. One reason for this is to provide the road surface with a slight angle to provide a run-off for rain. Another situation in which this occurs is when cutting a gutter or similar channel along the edge of a road. The end protector is preferably configured so as to provide protection to the side of the working element during such operations and such blade and working element orientations.
It should be noted that although mention has mostly been made of the mounting of the working element to a blade, the working element may be mounted to any suitable support and device, and for example may be mounted to a moldboard or the like of a vehicle. It should also be noted that the picks 3 are also often referred to as tools and also as pins or bits.
The present invention also extends to a working element having an end protector in accordance with any of the above features; a blade or other support assembly having such a working element; a surface working device having any of the preceding features, and a surface working vehicle having such a blade assembly or any of the other preceding features. It further extends to a method of protecting a leading edge of a working element using an end protector as described above in any of its variations.
Viewed from a further aspect, the present invention provides an end protector for a working element of a surface device, the working element having a plurality of pick holes therein for receiving pick elements, wherein the end protector includes:
a recess for receiving an end portion of the working element, such that at least one of the pick holes lies within said recess; and
a fastening element having a shank portion for extending into the pick hole, and a head portion for bearing against the end portion about the pick hole to urge the working element and end protector together.
Viewed from a still further aspect, the present invention provides an end protector for a working element of a surface device, the working element having a plurality of pick holes therein for receiving pick elements, wherein the end protector includes:
a body having a recess for receiving an end portion of the working element, such that at least one of the pick holes lies within the recess; and
a fastening element having a shank portion for extending through a first portion of the end protector body, through the pick hole and into a second portion of the end protector body.
Viewed from another aspect, the present invention provides a working element and end protector for a surface working device, wherein:
the working element has a plurality of pick holes therein for receiving pick elements;
the end protector includes a body portion that is mounted on an end portion of the working element, and a fastening element that extends into one of said pick holes for holding the end protector body potion in place on the working element.
In all of the above, the mounting of the end protector in a pick hole of the working element has the further advantages that the end protector can be easily removed and replaced, and that the end protector can be retrofitted to existing blade assemblies.
The invention may also however be seen to reside in the provision of an end protector integrally with the working element. Thus, an end protector of suitable shape could be integral with the working element, e.g., it could comprise a suitably hard material mounted on and about the leading edge of the working element at suitable locations.
Also, the working element could include a suitably formed connection portion to which the end protector may be mounted without the use of a pick hole, this portion being part of the body portion of the working element that houses the picks.
Such a portion could include for example a hole or recess for an end protector fastening element, such as a bolt, the hole or recess not being for the purposes of mounting a pick, but being provided and configured to receive the fastening element and/or a portion of the end protector.
The present invention therefore extends also to an end protector and working element for a surface working device, the working element having a plurality of pick holes therein for receiving pick elements, wherein:
the working element includes a mounting hole therein for mounting the end protector to the working element, said mounting hole being oriented generally in the same direction as the pick holes;
and wherein said end protector includes a fastening element for fastening said end protector to said working element, said fastening element extending into said mounting hole in use.